Category Archives: NMNH

Over the past few months, I’ve been writing about the strengths and weaknesses of various large-scale paleontology exhibits from an educational standpoint. Check out the Introduction, Walk Through Time, Phylogeny, and Habitat Immersion posts if you’d like to catch up. I’ll wrap up this series for the time being with a look at two upcoming renovations of classic fossil displays, which appear to have converged on similar aesthetic, organizational, and interpretive approaches.

First up is the Peabody Museum of Natural History, where the Great Hall of Dinosaurs and adjacent Hall of Mammal Evolution have seen little modification since the 1950s. While the PMNH fossil galleries are fascinating as a time capsule of mid-century exhibit design, much of the content is rather dated and a thorough overhaul is sorely needed. PMNH staff started planning for the renovation in 2010, and I highly recommend Collections Manager Chris Norris’sblog postson the process. Once the basic layout and concepts were in order, the museum hired the architectural firm Studio Joseph to prepare the images being used to promote the project. Fundraising is now underway, but an estimated completion date has yet to be announced.

Conceptual render of the Great Hall of Dinosaurs by Studio Joseph. Source

The big idea behind the new exhibit is the dynamic relationship between the biosphere and the Earth’s various other spheres (atmosphere, geosphere, hydrosphere, etc). The evolution of life on Earth did not occur in a vacuum, but as part of a continuously changing global system. This narrative does have a time axis – visitors will travel from the Permian at one end of the exhibit to the Quaternary at the other – but the precise divisions of geologic time are de-emphasized in favor of the broad environmental transitions that triggered evolutionary innovations. Examples might include the separation of continents during the Mesozoic, the diversification of flowering plants in the Cretaceous, or the massive climatic shift at the end of the Eocene. In this context, it’s more important that visitors understand (for example) that the Cenozoic was generally a transition from hot and wet to cold and dry (and the implications on mammalian evolution) than that they know the names and time spans of each epoch.

This approach contrasts sharply with traditional chronological exhibits, such as the Field Museum of Natural History’s “Evolving Planet.” The FMNH fossil galleries are extremely linear, and each geologic period is introduced with a set of easily-digested bullet points summarizing what happened during that time. Relatively tight spaces prevent visitors from seeing specimens from other time periods prematurely, and the galleries devoted to each period are color-coded to make them immediately distinct. According to Norris, this segmented presentation of the history of life obscures the large-scale transitions which transcend the somewhat arbitrary divisions of geologic time. As such, the new PMNH fossil halls will present the narrative holistically, encouraging visitors to track the underlying environmental trends that precipitated evolutionary change over time.

As is immediately clear from the promotional images, the new exhibit will juxtapose a modern, wide-open aesthetic with elements of the museum’s past – specifically, the outdated but gorgeous Rudolph Zallinger murals. Both of these design elements tie directly to exhibit’s narrative themes. By breaking up the central dinosaur pedestal and eliminating the unsightly glass cases in the Mammal Hall, the exhibit designers have dramatically increased the available floor space and opened up new lines of sight. This should allow visitors to view each of the galleries comprehensively, rather than as a series of discreet segments. Meanwhile, the Zallinger murals will remain a celebrated part of the exhibits. These magnificent frescoes were painted between 1942 and 1967, and are among the most iconic images of prehistoric life ever created. Although the physiology of some of the animals is outdated, Zallinger was in other ways ahead of his time. Rather than giving the geologic periods hard borders, Zallinger artfully wove the sections together so that each one fades imperceptibly into the next. The viewer can see that the flora, fauna, and climate are changing over time, but it’s a gradient, not a ladder, which perfectly reflects the narrative of the new exhibit.

A conceptual render of Deinonychus and other Cretaceous fossils. Source

About 300 miles south of PMNH, the re-imagining of the fossil halls at the National Museum of Natural History is well underway. This building’s east wing has been home to paleontology displays since it opened in 1910 and has been updated several times, but this is the first time it has undergone a complete, wall-to-wall modernization. The old exhibits were formally closed on April 28th, 2014, and NMNH staff spent the following year removing thousands of specimens from the halls. With the fossils out of the way, the next step will be to restore the historic space to its original neoclassical glory. After that, the new exhibits and updated fossil mounts can be assembled in time for a 2019 re-opening.

Intriguingly, the planned design of the new National Fossil Hall is both thematically and aesthetically similar to the PMNH renovation, albeit on a grander scale. The National Fossil Hall’s narrative focus will be on large-scale environmental transitions over time, and how these changes drove the evolution of plants and animals. Like at PMNH, this will be accentuated by an open layout: false walls and barriers that have divided the space since the early 1960s will come down, allowing visitors to see clear across the spacious three-story hall. This airy aesthetic hearkens back to the Hall of Extinct Monsters, and like the restoration of the Zallinger murals at PMNH it represents an admirable celebration of the institution’s history.

Early conceptual render of the National Fossil Hall by Reich + Petch Source

One interpretive choice that will set the National Fossil Hall apart is the clustering of specimens on islands, or “pork chops”, as the were called early in development. Each pork chop represents North America at a particular period in time. While anchored by a few charismatic mounts, the pork chops will also include all manner of small animals, invertebrates, and plants that were part of that environment. In this way, the islands are self-contained mini exhibits, each one showing a complete ecosystem that existed at a particular time. Moving among the these displays, visitors should get a sense of how climate change and faunal interchange (among other phenomena) can completely transform an ecosystem over millions of years. They’ll also learn how certain organisms, like sauropods in the Jurassic or grass in the Neogene, can change landscapes and influence the evolution of contemporary plants and animals.

The emphasis on open spaces and freedom of movement is notable, because this is quite different from the linear exhibits of the late 20th century. In recent decades, exhibits have become increasingly structured, with specific learning goals and physical spaces designed to corral visitors through a carefully orchestrated narrative journey. Again, Evolving Planet at FMNH is an excellent example of this philosophy. The new National Fossil Hall is in some ways a push in the opposite direction – although it has a clear narrative and overarching message, visitors can roam through the exhibit as they please. I see the pork chop system as a way to have it both ways. Whether visitors work through the exhibit front to back or run straight to the T. rex in the center of the hall, then wander around at random, they’ll still be able to compare and contrast the different ecosystems and learn what the designers want them to learn.

Early concept art of the Jurassic “pork chop.” Image from The Last American Dinosaurs, NMNH.

More than anything else, what I expect to set the National Fossil Hall apart from peer exhibits will be its explicit connections to modern-day environmental crises. It’s worth quoting the Department of Paleobiology’s summary in full:

Visitors to the Museum will be able to explore how life, environments, and ecosystems have interacted to form and change our planet over billions of years. By discovering and harnessing the tools and methods paleobiologists use to study fossils, visitors will gain a deeper understanding of how the world works.

The distant past affects all of us today and will continue to do so in the future. How will climate change impact the natural world and our daily lives? How can we make informed choices about our ecosystems as individuals and as a species? How can we all become informed citizens of a changing planet?

We are in the midst of an extinction event of our own making. Anthropogenic climate change, habitat destruction, and invasive species are as dangerous as any asteroid, and will likely have profound effects on our own lives and livelihoods in the coming century. But while humans are undeniably the cause of the latest round of global changes, we also have the power to mitigate and manage their consequences. The study of fossils provides important contextual information – we can place modern organisms in an evolutionary context and understand their role in shaping the world as we know it, and we can see how organisms have responded to significant environmental overhauls in the distant past. The fossil record is in fact the only way to directly observe these things (as opposed to relying on models or actualistic experiments). As such, the new National Fossil Hall will make it clear that paleontology isn’t just about historical curiosity. The study of past life gives us a long view of the Earth’s biotic and abiotic systems, and helps us predict how they will respond to today’s environmental changes.

Concept drawing of the National Fossil Hall’s Cretaceous zone. In the old hall, the viewer would be standing at the base of the mezzanine stairs facing the rotunda. Source

With the modern climate crisis front and center, the new National Fossil Hall has the potential to be one of the most immediately relevant and important paleontology exhibits ever assembled*. This is significant, because as I lamented when I started this series, immediacy and relevance are not things that most museum visitors expect from fossil displays. While fossils, particularly the mounted skeletons of dinosaurs and other prehistoric animals, have been central to the identity of natural history museums since the late 19th century, most visitors don’t regard these exhibits as anything more than prehistoric pageantry. Visitor surveys consistently reveal that dinosaurs are seen as eye candy – monsters that might as well be from another planet. This is a shame, because dinosaurs and other prehistoric organisms were real parts of our own world, and we can learn much from them.

The new National Fossil Hall will be arranged in reverse chronological order – as visitors move accross the gallery, familiar elements of modern environments will be stripped away and the world will become an increasingly alien place. Source

And so we come full circle. What is the point of a museum exhibit**? Is it enough to provide visitors an opportunity to see cool objects and specimens? When we ask museumgoers what they want to see, they tell us “dinosaurs” or “fossils.” They don’t ask for compelling narratives or connections to big contemporary issues, and they don’t see their museum visit as an important way to bridge gaps in scientific literacy.

Still, it is of critical importance that we provide these narratives and connections. Even if we accept the fact that the very existence of a museum and the chance to see real specimens is a Good Thing, museums are still accountable to the public. Virtually all museums cite education as the primary purpose of their institution, and it’s imperative to live up to that. A museum should have a learning goal in mind, it should be able to prove that this message is coming across, and it should be able to articulate why its audience is better off for it. This is not necessarily easy – exhibits need to be relevant without being condescending or preachy. Exhibit designers need to understand their visitors as much as their content. They need to find a balance between feeding visitors information and providing a customizable experience for diverse audiences. As we have seen, not every exhibit succeeds, but my impression is that we’re getting better at it.

*It’s also notable that this climate change-focused exhibit will be on the national mall, given the ongoing politically-motivated opposition to climate science.

**Note that I’m referring specifically to public-facing exhibits. There are many good reasons why the ongoing maintenance of natural history collections is intrinsically valuable.

References

Marsh, D.E. (2014). From Extinct Monsters to Deep Time: An ethnography of fossil exhibits production at the Smithsonian’s National Museum of Natural History. http://circle.ubc.ca/handle/2429/50177

The frentic search for North American dinosaur fossils in the late 19th and early 20th centuries can be divided into three phases. First came O.C. Marsh and E.D Cope, whose infamous rivalry resulted in literal trainloads of fossil material and laid the groundwork for our present understanding of dinosaur diversity. Next, teams sponsored by the newly-formed American, Carnegie, and Field museums returned to the same hunting grounds in the western interior to secure display-worthy specimens for their great halls of exhibition. The final phase was smaller in scale but yielded dinosaur specimens so spectacularly complete that most have gone unmatched to this day.

This third fossil rush occurred not in the United States but in Canada, along the cliff-like banks of Alberta’s Red Deer River. Fossil hunting in this region was pioneered in the late 1800s by George Dawson, Joseph Tyrell, and Lawrence Lambe, all working for the Canadian Geological Survey. This success did not go unnoticed by the the American Museum of Natural History’s Department of Vertebrate Paleontology. In 1910, the museum mounted an expedition led by Barnum Brown to the Red Deer River. Rather ingeniously, Brown’s team acquired a pair of 30-foot floating barges, which were used as mobile platforms from which they could excavate the steep river banks. The barges also served as floating campsites and a handy means of transportation in a region without reliable roads.The adventurous Brown was already a media favorite, and the publicity surrounding his Alberta expeditions only increased when the team started bringing back fully articulated and nearly complete dinosaur skeletons (including several with skin impressions).

Under pressure from constituents concerned that the Americans were hauling away so much of their natural heritage, the Canadian government formed its own team of fossil collectors in 1912. The new Canadian Geological Survey team was headed by independent fossil hunter Charles H. Sternberg (a veteran collector who had once worked for Cope) and his sons George, Levi, and Charles Jr. The Canadian and American teams worked in the same region for the next five field seasons. Their rivalry was usually good-natured, but on more than one occasion Brown saw fit to grumble about the Sternbergs’ ethics (never mind that he was the one permanently removing fossils from their country of origin).

All of this is so much preamble for the actual topic of this post – three remarkable Gorgosaurus skeletons* collected near the Red Deer River during the Canadian fossil rush. All three were eventually mounted in relief by AMNH preparator Peter Kaisen, and for a time they were displayed together in the Hall of Fossil Reptiles. These specimens are on the short list of most complete large theropod dinosaurs ever discovered, and in their day they provided researchers an unprecedented look at the physiology of these amazing animals. Nearly a century later, the three mounts are virtually unchanged. Locked behind glass for decades and largely inaccessible to researchers, the mounts themselves are now relics of a fascinating transitional period in the history of dinosaur studies.

As usual, a brief explanation of nomenclature is required. William Matthew and Barnum Brown originally described these specimens as Gorgosaurus, a genus that Dale Russell sank into Albertosaurus in 1970. Most specialists no longer support this synonymization, but the specimens at AMNH are still labeled as Albertosaurus.

Gorgosaurus libratus – USNM 12814

A recent photo of USNM 12812 from the ongoing renovation of the national fossil hall. Source

USNM 12814 (originally designated AMNH 5248) was excavated by Brown’s company in 1913 and prepared for display in 1918. Kaisen elected to recreate the death pose in which the Gorgosaurus was found, with its head swept backward over its body. All told, the finished mount included a skull, a complete set of cervical and dorsal vertebrae, complete forelimbs, and a single femur – the pelvis and the rest of the hindlimbs were filled in with casts from other specimens. Since the skeletonwas mounted in relief, Kaisen simply painted the tail onto the backdrop.

After at least a dozen years on display at AMNH, the Gorgosaurus was traded to the National Museum of Natural History as part of a complicated deal between the two museums. While surveying fossil collections throughout the United States, Brown realized that a single Barosaurus skeleton from Dinosaur National Monument had been divided among three different institutions. NMNH had the neck and part of one forelimb, the Carnegie Museum had the tail, and the University of Utah had the rest. Between 1929 and 1933, Brown arranged a series of trades in order to unify the Barosaurus at AMNH. The Smithsonian in particular drove a hard bargain – the museum had already invested $3400 in preparing their Barosaurus section, and paleontology staff wanted a good return for their investment. Brown’s initial offer was the fully prepared and mounted Gorgosaurus. Although AMNH valued the field and prep time spent on the fossils at $4573, it was at that point a duplicate specimen taking up valuable space in their increasingly crowded exhibit hall.

NMNH dinosaur specialist Charles Gilmore confided in Brown that he was okay with this trade, but fellow Smithsonian paleontologist Alexander Wetmore wasn’t sold. For years, NMNH staff had been trying to acquire one of the many Moropus specimens AMNH had collected at the Agate Fossil Beds in Nebraska.NMNH had offered a variety of specimens to trade, even sending AMNH a set of brontothere skulls at one point, but AMNH was adamant the Moropus fossils could only be exchanged for cash. Brown really wanted that Barosaurus neck, so in January of 1933, he finally relented and offered the Smithsonian a largely complete Moropus in addition to the Gorgosaurus. Not long after, the Gorgosaurus relief mount found its way into the Hall of Extinct Monsters at NMNH.

Gorgosaurus sp. – AMNH 5458

Brown’s team found their second Gorgosaurus near Steveville, Alberta in 1914. Complete save for the left leg, right arm, and parts of the rib cage and tail, the mount was ready for display in May of 1921. At 24 feet long and 14 feet high, this was by far the largest relief mount at the museum. In fact, it was too big to fit through the workshop doorway in one piece, so Kaisen constructed it in eight sections that were sealed together in the exhibit hall. Each section had its own wooden frame for support, and the bones themselves were held in place with steel straps. The skull, jaw, and left forearm could be removed for individual study. This was unusual for the period (most contemporary fossil mounts were designed to be permanent) and speaks volumes about this specimen’s unique scientific value.

This mount is particularly notable for its awkward running pose. Directly contradicting many narratives of early 20th century paleontology, Matthew and Brown envisioned Gorgosaurus as an animal that “walked and ran much like a gigantic bird.” The AMNH team posed this mount after studying photos of bipedally running lizards, particularly the western tiger lizard*. However, Matthew and Brown noted that the dinosaur’s limb proportions and range of motion more closely resemble a bird than a lizard, and adjusted the pose accordingly. They also advised a more conservative stride length to compensate for the animal’s considerable weight.

*Matthew and Brown do not provide a scientific name, and the common name “western tiger lizard” doesn’t seem to be used any more. Anyone know what it’s called today?

The final pose was a compromise between the elevated torso of a running lizard and the comparatively tight gait of a bird. It looks more than a little strange, but AMNH 5458 is certainly closer to our present understanding of theropod posture than most mounts of the era. Matthew and Brown’s interpretation of Gorgosaurus turned out to be ahead of its time. Some contemporary researchers, including Lawrence Lambe, declared the running pose to be highly improbable, and virtually all theropod mounts constructed over the next 60 years returned to the tail-dragging posture of the 1915 AMNH Tyrannosaurus.

Gorgosaurus “sternbergi” – AMNH 5664

Gorgosaurus “sternbergi” as it was discovered and originally mounted. Source

The most complete tyrannosaur from the Red Deer River was not collected by the AMNH party, but by the Sternbergs. The elder Charles Sternberg discovered the specimen in 1917, entirely intact save for the left arm and the very end of the tail. In fact, this was the most complete large theropod ever found in North America until it was surpassed by yet another Gorgosaurus, TCM 2001.89.1. Sternberg first attempted to sell the specimen to the British Museum. They weren’t interested, but AMNH was. In 1918, the Department of Vertebrate Paleontology bought the skeleton for $2000, thus completing the tyrannosaur trio.

Matthew and Brown described AMNH 5664 as a new species – Gorgosaurus sternbergi. In their 1921 publication, they describe the skull as longer and shallower than other Gorgosaurus specimens, with rounder orbits. However, Brown and Matthew recognized that these could be juvenile characteristics, noting as well that the unfused pelvic bones were an indication of immaturity. As early as 1970, this specimen was suspected to be a juvenile Gorgosaurus (or Albertosaurus) libratus.

Kaisen prepared the relief mount in 1921, this time assisted by Carl Sorenson. The photo above shows the original version of this mount, with the tail projecting straight back from the body. This was how Sternberg discovered the skeleton, and Kaisen wanted to keep the death pose intact. In the 1950s, the tail was “corrected” to make it drag on the ground. Although the display has not been altered since, the revised tail posture is now considered inaccurate. Indeed, the vertebrae apparently had to be angled unnaturally to make the dragging tail work at all.

All three Gorgosaurus specimens were first displayed in the cramped quarters of the Hall of Fossil Reptiles (now the Hall of Primitive Mammals) with the rest of the growing AMNH dinosaur collection (USNM 12814 and the tail of AMNH 5664 are barely visible in this photo). 5458 and 5664 moved to the newly opened Great Hall of Dinosaurs in 1922. They flanked the gallery’s rear doorway for 70 years before being moved to the Hall of Saurischian Dinosaurs in 1994. Meanwhile, the Gorgosaurus transferred to the Smithsonian first appeared in the Hall of Extinct Monsters in the 1940s, displayed behind glass on the north wall. It switched to the south side in 1962, and moved about 30 feet up the wall in 1981, where it could only be properly seen from the mezzanine ramp.

Aside from the aforementioned alternation to AMNH 5664’s tail, the Red Deer River Gorgosaurus trio has not been modified since they were first built. This may well change in the not-to-distant future. The NMNH crew is hard at work on a thorough renovation of the national fossil hall, dismantling and restoring all of the classic dinosaur mounts. Meanwhile, the current AMNH paleontology exhibits are now 20 years old, and will soon be due for a similar overhaul. Both institutions will need to decide whether or not to free the Gorgosaurus specimens from their plaster substrate. This would be an extremely difficult process, but not impossible – Phil Fraley Productions recently rebuilt the Carnegie Museum’s Corythosaurus, Dryosaurus, and Camptosaurus as free-standing mounts. Dismantling the relief mounts would give a new generation of scientists access to these important specimens, and it would allow for the skeletons to be given more accurate poses. In addition, a standing Gorgosaurus mount alongside either museum’s Tyrannosaurus rex would be both informative and awesome.

Nevertheless, remaking these mounts would also destroy significant historical context. The carefully restored death pose of USNM 12812 seems like something worth preserving, and the AMNH specimens represent an important transitional period in the history of dinosaur science. In the past, museums have often taken a “science marches on” approach when updating aging displays, but in these mounts might be unique enough in their current form to be left as-is. What do you think?

Some time ago, I wrote about the O.C. Marsh dinosaurs at the National Museum of Natural History. These are the mounted skeletons made from the enormous collection of fossils Marsh accumulated while working for the United States Geological Survey – if you’d like, you can catch up with Part 1 (on Edmontosaurus and Triceratops) and Part 2 (on Camptosaurus, Ceratosaurus, and Stegosaurus). Looking back, I noticed that I never actually finished, so here are the two Marsh dinosaurs with as-yet untold stories.

The Thescelosaurus

The name Thescelosaurus neglectus means “neglected wonderful lizard”, because Smithsonian paleontologist Charles Gilmore found the original specimen at the bottom of a crate, more than 10 years after it arrived at NMNH. Still buried its its field jacket, this skeleton had been long overlooked by both Marsh and the museum staff. Nevertheless, Gilmore found that it was remarkably complete and that it represented a taxon new to science.

An illustration of the Thescelosaurus holotype prior to reconstruction. Source

Thescelosaurus as displayed after 1981. Photo by Chip Clark.

The specimen that would become the Thescelosaurus holotype (USNM 7757) was excavated by John Bell Hatcher and William Utterback in July of 1891, while they were collecting for Marsh in Niobrara County, Wyoming. 20 years later, Gilmore discovered that the skeleton was articulated and intact, save for the head, neck, and parts of the shoulder. He even found small patches of preserved skin on the tail and legs. According to Gilmore, the animal had been buried rapidly after death, since it showed no signs of dismemberment by scavengers.

After describing the fossils, Gilmore mounted the Thesclosaurus in relief on its left side. Other than the reconstructed skull (modeled after Hypsilophodon), the specimen was displayed almost exactly as it was found. This was important to Gilmore, because as he wrote in his published description, “I am…of the opinion that specimens so exhibited hold the attention of the average museum visitor far longer and arouse a keener interest in the genuineness of the specimen than does a skeleton that has been freed from the rock and mounted in an upright, lifelike posture.” Today at least, I suspect that the opposite is true – visitors are generally more impressed by dynamic standing mounts than by reliefs that preserve death poses. Still, it’s fascinating to gain a small amount of insight into the motivations of a pioneering mount-maker.

Although it was first displayed in the Hall of Extinct Monsters, the Thescelosaurus was most prominently exhibited in the 1963 version of the NMNH fossil halls. Here, it joined the Edmontosaurus, Gorgosaurus, and partial Corythosaurus relief mounts along the south wall. In life, these animals were vastly removed from one another in time and space, but displayed together they almost appeared to be parts of a single quarry face. The Thescelosaurus moved to the north wall in 1981, unfortunately placed rather high and out of most visitors’ line of sight.

When the new National Fossil Hall opens in 2019, USNM 7757 will be replaced with a duplicate cast. The original bones will be moved to the collections, where they can be properly studied for the first time in a century. Already, technicians at Research Casting International have freed the skeleton’s left side, which had never been fully prepared. The exhibit replica assembled by RCI is beautiful, retaining the ossified tendons and cartilage impressions of the original. Mounted in a running pose, the new cast also features an updated head, based on Clint Boyd’s recent description of Thescelosaurus cranial anatomy.

The Allosaurus

Built in 1981, the Allosaurus fragilis (USNM 4734) was the last Marsh Collection dinosaur to be mounted, although bits and pieces have been on display at NMNH since 1920. There has been considerable interest in this individual recently, in part because Kenneth Carpenter and Gregory Paul proposed in 2010 that it become the neotype for Allosaurus – more on that in a moment. Others are interested in this specimen because of its unique pathologies. In addition to several broken and healed bones, the Allosaurus has a massive puncture wound on its left scapula, which nicely matches the diameter of a Stegosaurus tail spike.

Benjamin Mudge collected this specimen in 1877 near Cañon City, Colorado. Known as the Garden Park quarry, this site also produced the Stegosaurus, Camptosaurus, and Ceratosaurus on display at NMNH. Although the Smithsonian obtained the Allosaurus with the rest of the Marsh Collection around 1900, Gilmore did not look at it (or any of the theropod material) until at least 1911. All told, USNM 4734 consists of a partial skull and jaw, a complete set of presacral and sacral vertebrae, a few ribs, a pelvis, and virtually complete arms and legs. It would have had a tail as well, but Mudge’s crew accidentally threw the articulated tail over a cliff while excavating the skeleton. Norman Boss assembled a reconstructed skull, which was displayed through the 1970s. The articulated legs and feet were exhibited in a free-standing case until the late 1950s.

This specimen’s taxonomic history merits some discussion. The holotype Marsh selected when naming Allosaurus (YPM 1930) is notoriously poor, consisting of a single phalanx, two dorsal centra, and a tooth. Dozens of very complete skeletons attributed to Allosaurus are now known, and most specialists basically agree on what an Allosaurus is, but the lack of a usable type with which to define the taxon has been an ongoing problem.

The far more complete USNM 4734 was recovered from the same quarry as the Allosaurus holotype, during the same 1877 field season. Marsh himself actually used this specimen, rather than his designated type, to illustrate subsequent publications on Allosaurus. In 1920, Gilmore flirted with the idea of nominating USNM 4734 as a neotype for Allosaurus, but for reasons that I find difficult to follow, he decided to lump both specimens into the older name Antrodemus valens. Joseph Leidy coined Antrodemus in 1870 based on a single caudal vertebra with no geologic provenance, so this move did little to fix the underlying issue. Nevertheless, Antrodemus remained a popular synonym for Allosaurus in some circles for several decades.

When the NMNH fossil halls were renovated in 1981, the designers noticed that the exhibit badly needed a large theropod mount. Arnold Lewis was tapped to design and construct a complete mounted version of USNM 4734, with some assistance from Ken Carpenter. The tail was cast from a Brigham Young University specimen, but Lewis sculpted the belly ribs and sternum using an alligator skeleton as reference. The completed Allosaurus measures 17 feet from its grinning jaws to the tip of its tail, and a form-hugging armature makes itlook particularly dynamic. This mount has been a favorite among visitors for more than 30 years, although the 2001 addition of a Stan the Tyrannosaurus cast has somewhat overshadowed the smaller theropod.

The complete Allosaurus skeleton was finally exhibited in 1981. Photo by the author.

Technicians from Research Casting International took down the Allosaurus in the summer of 2014 as part of the current round of renovations. You can watch a video of the de-installation here. The skeleton will be remounted in a few years (crouching beside a nest mound), but Smithsonian researchers want to get a good look at it before that happens. In particular, curator Matt Carrano has been wondering for some time whether a partial jaw Marsh named “Labrosaurus ferox” actually belongs to this specimen. The “Labrosaurus” jaw, which has an unusual pathology caused by a bite or twisting force, came from the same quarry as USNM 4734, and appears to be the same portion of jaw that the more complete skeleton is missing. Time will tell whether Carrano’s hunch is correct. Meanwhile, Carpenter and Paul’s petition to replace the Allosaurus type with this more complete specimen from the same locality is still pending. We should expect to hear more about that soon, as well.

References

Gilmore, C. M. (1915). Osteology of Thescelosaurus, an ornithopodus dinosaur from the Lance Formation of Wyoming. Proceedings of the U.S. National Museum 49:2127:591–616.

Gilmore, C.M. (1920). Osteology of the Carnivorous Dinosauria in the United States National Museum with Special Reference to the Genera Antrodemus (Allosaurus) and Ceratosaurus. United States National Museum Bulletin 110:1-154.

In the middle decades of the 20th century, museum theory and paleontological science were undergoing complementary revolutions. Museum workers shrugged off their “cabinet of curiosity” roots and embraced visitor-centric, education-oriented exhibits. Designers began to envision the routes visitors would travel through an exhibit space, and consider how objects on display could contribute to holistic stories. Meanwhile, paleontologists like Stephen J. Gould and David Raup moved their field away from purely descriptive natural history, exploring instead how the fossil record could inform our understanding of evolution and ecology. The common thread between both transitions was a focus on connections – bringing new meaning and relevance to disparate parts by placing them in a common narrative.

Between 1953 and 1963, the Smithsonian implemented an institution-wide modernization program, transforming virtually every exhibit in the museum complex. The National Museum of Natural History began renovations to its classic fossil halls in 1959, and the new exhibits were emblematic of contemporary trends in both museum design and paleontology. The plan, as devised by exhibit designer Ann Karras, was to do away with the loose arrangement of specimens and turn the east wing into a guided narrative of the biological and geological history of Earth. Responsibility for selecting specimens and writing label copy in each of the four halls fell to a different curator. In Hall 2, which housed dinosaurs and fossil reptiles, that curator was Nicholas Hotton.

Layout of the NMNH east wing as of 1963.

Hotton joined NMNH in 1959 as an Associate Curator of Paleontology. Entirely onboard with Karras’s vision and the paleobiology movement as a whole, Hotton described the old exhibits as “crowded” and “unorganized.” He thought NMNH had plenty of dinosaurs, but “mammal-like reptiles”* were sorely needed if Hall 2 was to tell the complete story of amniote evolution. Following that, Hotton’s mission over the next several years was to assemble a respectable collection of synapsid specimens for NMNH, and to incorporate them into a well-illustrated exhibit on the origins of mammals. This post highlights just a few of the specimens featured in Hotton’s version of Hall 2.

*In Hotton’s day, early mammalian relatives were usually called “mammal-like reptiles”, hence their inclusion in the fossil reptile exhibit. Today, most specialists prefer a more precise definition of reptiles that excludes synapsid (mammal-line) animals. In this post, I will be using the modern classification wherever possible.

The Dimetrodon

Prior to 1960, the non-mammalian synapsid collections at NMNH were mostly limited to early Permian pelycosaurs. The most impressive of these was a Dimetrodon gigas collected in 1917 by independent fossil hunter Charles Sternberg. One of the best collectors of his day, Sternberg worked intermittently for E.D. Cope, O.C. Marsh, and various North American museums. In the summer of 1917, however, Sternberg was on a personal collecting trip with his son Levi. Their target was the Craddock Ranch bone bed of Baylor County, Texas, which was first explored in 1909 by a University of Chicago team. Sternberg was already quite familiar with this part of western Texas, having made some of the first thorough surveys of the Permian “red beds” in the 1880s, but the site itself was new to him. Nevertheless, Sternberg was extraordinarily successful that summer, collecting hundreds of fossils from a wide range of animals. He offered this bounty to the Smithsonian, and they purchased it from him immediately.

The Craddock Ranch fossils were particularly appealing because of their unique preservation. Buried in soft clay at the bottom of a shallow pond, the fossils could be removed from the ground with relative ease, and were largely free of encrusting matrix. Although few of the bones were articulated, many were identifiable. All told, the Sternberg collection included at least 35 skulls and partial skeletons from amphibians like Cardiocephalus, Diplocaulus, and Seymouria, plus hundreds of individual Dimetrodon bones, and a single articulated Dimetrodon specimen.

An early photograph of the Dimetrodon mount. Image from Gilmore 1919.

The Dimetrodon was first displayed on the north wall of the Hall of Extinct Monsters. Source

That Dimetrodon (USNM 8635) was the basis for a mount constructed by T.J. Horne. The articulated skeleton included a complete series of presacral vertebrae, the shoulder girdles, most of the forelimbs, and the left femur and tibia. The skull and jaw bones were found disarticulated, but bound together in the same mass of matrix as the skeleton. Horne added the pelvic bones and sacrum from smaller Dimetrodon specimens, and sculpted the rest of the missing material in plaster to complete the mount. Notably, his reconstructed tail was extremely short and stubby. Although the American Museum and Field Museum already had Dimetrodon mounts on display, the NMNH version stood out because of its open jaws, which Charles Gilmore said “gives the animal an appearance of angrily defying one who has suddenly blocked his path.”

Gilmore added the Dimetrodon to the Hall of Extinct Monsters in 1918. Like the other standing mounts constructed under Gilmore’s supervision, the skeleton was placed on a base textured and painted to resemble the rocks in which it was found. At this point in time, the NMNH fossil halls lacked any overarching organizational scheme, and interpretive content was minimal. Nevertheless, Gilmore displayed the Dimetrodon mount with both a small model and a 15-foot oil painting by Garnet Jex, which provided general audiences a better understanding of the animal’s life appearance.

During the 1962 renovation, Hotton re-contextualized the classic Dimetrodon mount as a mammal ancestor. Unmissable orange arrows pointed to the specific anatomical traits that signify the animal’s kinship with mammals, including heterodont teeth and a single temporal fenestra. By design, visitors would pass Dimetrodon before visiting the true mammals in the adjacent hall.

The Dimetrodon skeleton itself was altered during the next renovation in 1981, when it was placed on a new, untextured base and given a longer replica tail. Contemporary staff also repainted the plaster sections to more closely resemble the original fossils – a surprising reversal of Gilmore and Horne’s original intention to make the reconstructed bones obvious to viewers.

The Thrinaxodon

Pelycosaurs like Dimetrodon represent the first major synapsid radiation, but by the middle Permian they were almost entirely replaced by therapsids. A more derived group which includes modern mammals, therapsids spread across the globe and became increasingly diverse as the Permian progressed. From weasel-sized burrowers to multi-ton herbivores, non-mammalian therapsids were among the first animal groups to conquer a wide range of terrestrial niches. Hotton wanted to tell this story in the modernized fossil exhibit, but there were hardly any non-mammalian therapsids in the NMNH collections. To correct this problem, Hotton took to the field for several months in 1960, and again in 1961. He joined James Kitching in exploring the Beafort Group rocks of South Africa, which were known to produce plentiful Permian and Triassic vertebrate fossils. Hotton returned to the museum with over 200 new specimens, the best of which were used in the renovated exhibit.

Hotton’s most prized find from South Africa was a gorgeously preserved and nearly complete Thrinaxodon liorhinus (USNM 22812). Hotton called this specimen “Baby Doll”, and while it was not prepared in time for Hall 2’s 1963 opening, it would later earn a spot of honor in the exhibit. Before that happened, though, Baby Doll was actually stolen by an over-enthusiastic volunteer. The FBI located and returned the fossil a year and a half later.

Since the 1980s, the Thrinaxodon has been displayed alongside the skull of Cynognathus crateronotus (USNM 22813), which Hotton collected on the same expedition. Both are members of the cynodont clade, which includes some of the closest relatives of modern mammals.

The Daptocephalus

Less than a month after hall 2 reopened, Nicholas Hotton returned to South Africa. This time, he was accompanied by his spouse Ruth Hotton and their three young children. For seven months, the Hottons traveled among fossil sites on different ranches, camping most nights. They collected some 300 specimens for the Smithsonian, and Hotton’s biostratigraphic mapping of the Beaufort Group brought a measure of clarity to this region’s historically convoluted geology.

Ruth Hotton made one of the trip’s most impressive finds while prospecting in a dry riverbed with her daughter, Carol (who is now a paleobotanist at NMNH). Turning a corner, she stumbled upon a dicynodont skeleton, completely exposed and lying in the middle of the channel. One can only imagine the surprise and delight of finding an articulated fossil skeleton completely uncovered. If the Hottons had been there one season earlier or one season later, the river would have undoubtedly destroyed the fossils.

Daptocephalus on display. Photo by James Di Loreto, National Museum of Natural History.

Back at the museum, Nicholas Hotton prepared the specimen (USNM 299746) and determined it to be Daplocephalus leoniceps, one of the plethora of dicynodonts known from the Beaufort Group. Based on this classification, he reconstructed the damaged skull to resemble more complete Daplocephalus specimens, and added casts of Daplocephalus limbs.

The specimen was restored in 2019 and is now labeled Platypodosaurus. Photo by the author.

As it turns out, however, USNM 299749 is not a Daplocephalus—it is a somewhat distantly related dicynodont currently called Platypodosaurus. To varying degrees, fossil mounts are hypotheses made of bone and plaster. They are based on the best information available at the time, but sometimes they need to be corrected. The NMNH “Daplocephalus” had been mislabeled and erroneously reconstructed for many years, but the 2014 renovation of the NMNH fossil halls now presented an opportunity to deconstruct the specimen and study it up close. As of 2019, Platypodosaurus was back on display with a newly reconstructed skull and limbs.

Thanks to Christian Kammerer for kindly sharing images and insight on “Daptocephalus”!

References

Gilmore, C.W. (1919). A Mounted Skeleton of Dimetrodon gigas in the United States National Museum, with Notes on the Skeletal Anatomy. Proceedings of the United States National Museum 56:2300:525-539.

About 150 million years ago, a severe drought ravaged the western interior of North America. In eastern Utah, malnourished dinosaurs gathered near a dwindling river. Unwilling or unable to leave the water source, they eventually died of thirst or disease. When rain finally returned to the region, three or four successive flash floods washed dozens of animal carcasses into a relatively small depositional area to the southeast. Today, this site is known as the Carnegie Quarry at Dinosaur National Monument, and it is one of the most incredible fossil sites in the world.

Today, a structure encompassing a 180-foot section of the deposit (less than half its total length) allows visitors to view nearly 1400 dinosaur bones in situ. However, the fossils on display at Dinosaur National Monument represent only a portion of the material found at the Carnegie Quarry. Between the site’s discovery in 1908 and the establishment of the quarry wall exhibit, more than 20 reasonably complete dinosaur skeletons and dozens more incomplete specimens were excavated and distributed to museums in the US and Canada. No less than eleven mounted skeletons have been created from this material, and they are all still on display today. Although they are thousands of miles from their place of discovery and exhibited in four different cities, these mounts all represent individuals that lived and died in the same environment. They may have even encountered each other in life!

The Discovery

Earl Douglass was already an established fossil hunter when the Carnegie Museum of Natural History hired him in 1902. Late in the 1909 field season, Douglass was prospecting near the confluence of the Green and Yampa Rivers when he spotted a series of sauropod vertebrae eroding out of the rocks. Once Douglass and his crew began excavating the fossils, it became apparent that they had not just one remarkably complete dinosaur, but several. Douglass called it a “beautiful sight,” and CMNH director William Holland could barely contain his glee in his reports back to the Pittsburgh museum. Under Douglass’s management, CMNH crews worked at what became known as the Carnegie Quarry for 13 years. The dinosaur fossils were jumbled and often overlaid one another, so the excavators had to work on multiple skeletons simultaneously. The especially hard sandstone also slowed their work, and the team regularly resorted to huge horse-drawn plows and even dynamite to reach the fossils. Eventually railway tracks were installed to help transport blocks of sandstone out of the quarry.

In 1915, Holland successfully petitioned Woodrow Wilson to preserve the site as a national monument. CMNH crews continued to excavate until early 1923. At that point, their primary benefactor Andrew Carnegie had died, and funding for field work was dwindling. Other museums collected from the quarry periodically in the years that followed, but Douglass’s idea to contain the remaining fossils in an on-site museum was not realized until 1958.

The Mounts

The CMNH Apatosaurus was the first dinosaur discovered at the Carnegie Quarry. After Douglass first spotted the articulated caudal vertebrae in August of 1909, his crew spent several months extracting the rest of the skeleton from the rocks. The excavation continued into early 1910, and by the time they were finished they had the most complete Apatosaurus ever found – a title the specimen holds to this day. Holland mounted the 77-foot skeleton alongside the museum’s Diplodocus in just three years, at the time a record for a sauropod mount.

Holland famously left his Apatosaurus headless for decades due to a disagreement with Henry Osborn of the American Museum of Natural History. Douglass recovered a skull that almost certainly belonged to the Apatosaurus, but Holland opted not to use it because it contradicted the sculpted head already in place on the AMNH Apatosaurus mount. After Holland’s death in 1932, museum staff quietly added a casted Camarasaurus skull as a placeholder. This was finally replaced with a proper Apatosaurus skull in 1979. More recently, the team at Phil Fraley Productions disassembled and restored the Apatosaurus, along with the rest of the classic CMNH dinosaurs. Since 2007, this specimen has been back on display in a more graceful modern pose.

When the CMNH team discovered this skeleton in 1912, they assumed it was yet another specimen of the well-known Diplodocus. It was harvested for parts, with portions sent to CMNH, the United States National Museum, and the University of Utah to supplement their displays. When the specimen turned out to be the more obscure sauropod Barosaurus, it languished in pieces for many years. Barnum Brown of AMNH was making a circuit of the fossil collections at various natural history museums when he rediscovered this specimen. Through a series of purchases and trades, the Barosaurus was reunited at AMNH in 1929.

Nevertheless, AMNH quickly abandoned plans to mount the Barosaurus – the museum already had a sauropod on display, and there wasn’t enough floor space for another one. It wouldn’t go on display until 1991, when Lowell Dingus conceived of the idea to mount the Barosaurus in a spectacular rearing pose as part of the renovation of the Theodore Roosevelt Rotunda. Peter May took on the project – one of the first mounts produced by his company Research Casting International. The resulting display, actually a cast, is the tallest free-standing dinosaur mount in the world.

Douglass recovered a second partial Barosaurus skeleton in 1912, which consisted of a mostly complete torso and parts of each leg. It stayed in the CMNH collections for many years, until they traded it to the Royal Ontario Museum in 1962. ROM staff intended to mount the skeleton, but once again this was cancelled due to a lack of space. David Evans was developing a new ROM paleontology exhibit in 2007 when he learned that the museum had most of a Barosaurus sitting in its collections. With only weeks remaining before the exhibit’s opening, Evans tapped Research Casting International to mount the sauropod, supplemented with a replica neck and tail from the AMNH version.

Several Allosaurus specimens are known from the Carnegie Quarry, but the one on display at CMNH is one of the largest. Douglass and his team excavated this 35-foot skeleton between 1913 and 1915. The mount was built in 1938. Although the specimen included a partial skull, the exhibit team swapped it with a cast of a more complete skull (also found in the Carnegie Quarry) from the collections of the University of Utah. Thismount also includes casts of the arms of USNM 4734, an Allosaurus collected for O.C. Marsh.

The CMNH Stegosaurus is a composite of several individuals excavated from the Carnegie Quarry between 1920 and 1922. Museum staff completed the 21 foot-long mount in 1940, using a skull cast from USNM 8612. Casts of this skeleton were distributed to several other museums at some point, one of which is on display at the University of Nebraska State Museum. Phil Fraley’s company remounted the CMNH original in 2007.

This juvenile Camarasaurus is the most complete sauropod ever found. It is displayed as a relief mount almost exactly as it was discovered, with two exceptions. The left leg was swapped with a more complete one from another individual, and the tail was re-positioned to create a more aesthetically pleasing mount. Casts of this skeleton are displayed at museums throughout the United States, including Dinosaur National Monument, but the original is at CMNH. This specimen is also notable because its left scapula is preserved in its life position, making it a helpful model for skeletal reconstructions and exhibit mounts.

NMNH Camarasaurus. Photo by the author.

Camarasaurus lentus – USNM 13786

The second best Camarasaurus also comes from Carnegie Quarry, but it is a considerably larger individual. Only the tail and a few odds and ends were missing. CMNH kept the specimen for several years before trading it to USNM in 1933 for a set of Pliocene horse skeletons. Norman Boss prepared the specimen in full view of the public during the 1936 Texas Centennial Exposition – one of the first known examples of such an exhibit. The completed mount appeared at USNM in the 1950s, sporting the tail of another Camarasaurus. At over 30 feet long, this skeleton is one of the largest dinosaurs on display at the Smithsonian. Unfortunately, the death pose somewhat limits the effect. The Camarasaurus was taken off exhibit in late 2014 for conservation and remounting. When it returns, it will be standing on its feet for the first time in 150 million years, taking its rightful place as one of the museum’s most impressive dinosaurs.

Since this Dipldodocus was found somewhat disarticulated, Douglass suggested that the carcass may have been twisted apart while rolling downstream. AMNH held on to this skeleton for some time before trading it to the Denver Museum of Nature and Science in 1936 for two mammoth skeletons. Preparator Phillip Reinheimer mounted the skeleton with the help of 40 workers assigned to the museum through the Works Progress Administration. Additional Diplodocus fossils collected by William DeWeese (actually the first dinosaur specimens acquired by the museum) were also used to complete the mount. The Diplodocus remained on view until 1989, when Ken Carpenter and others restored and remounted the sauropod, elevating its tail and making its neck sweep gracefully to the left. The improved mount has been on display since 1995.

Douglass found this controversial small ornithopod in 1922, and correctly matched it with an isolated leg several feet away. It was first identified as Camptosaurus medius, but in 2008 Ken Carpenter reassigned it to the new species C. aphanoecetes. A 2011 phylogenic study by Andrew McDonald moved this specimen to a new genus, Uteodon. Carpenter, however, asserts that McDonald’s analysis was based on an incorrectly associated Dryosaurus braincase.

CMNH staff assembled the fossils into a relief mount in 1940. The skull, hindfeet, and tail were all sculpted. During the 2007 renovation, the Phil Fraley Productions team extracted the fossils from the plaster slab, even managing to preserve the delicate ossified dorsal tendons. They then created a new, three-dimensional mount, which features a revised replica skull.

CMNH Dryosaurus. Historic photo from McGinnis 1982; modern photo by the author.

Dryosaurus altus – CM 3392

This Dryosaurus skeleton is the most complete of several collected at Dinosaur National Monument. The tail is missing, and given the completeness of the rest of the skeleton it may well have been destroyed when Douglass’s crew was blasting through rock to get to the bone layer. The Dryosaurus entered the CMNH collections in 1922, and was assembled as a 9 foot-long relief mount in 1940. In 2007, Fraley’s team removed the fossils from the plaster matrix, and just as they did with the Camptosaurus, constructed a standing mount. To date, this is the only mounted Dryosaurus specimen in the world. It is displayed alongside a juvenile Ceratosaurus castacquired from Western Paleontological Laboratories.

NMNH Diplodocus. Photo by the author.

Diplodocus sp. – USNM 10865

The National Museum of Natural History’s Diplodocus was one of the last articulated skeletons removed from the Carnegie Quarry. When the CMNH crew closed up shop, Charles Gilmore of the Smithsonian moved in to recover one of the sauropod skeletons Douglass left behind. In 1923, Gilmore’s team excavated a partial Diplodocus, and also cherry-picked a few extra bones from an adjacent specimen. The process of mounting the skeleton at USNM took six years of continuous work, and Gilmore would later describe it as the most ambitious undertaking his department hadever attempted. The 70-foot Diplodocus mount was completed in 1931, and remained unchanged for more than 80 years. It was finally taken down in December 2014, and will return in a new pose in 2019.

Addendum: Mike Taylor recently called attention to a gorgeous map of the entire deposit prepared by Ken Carpenter, which was what prompted this post. Check it out here.

Instead of repeating last year’s navel-gazing, I’m going to try something a little more interesting with my obligatory year-in-review*. This post will recap 2014’s big events in museum paleontology – I’ve covered some of it before, but there’s plenty that I missed as well.

Out with the Old

Concept art for the new NMNH fossil hall, opening 2019.

I don’t think it’s a stretch to say that the most important event in the world of fossil exhibits this year was the closing of the National Museum of Natural History’s east wing. This is the world’s most-visited natural history museum, and the fossil mounts on display here have been among the most widely-viewed anywhere. The east wing has been home to paleontology displays since the building opened more than a century ago, but until now it has never undergone a complete, wall-to-wall modernization. Since the halls closed in April, NMNH staff have made significant progress de-installing the old displays, including some mounted skeletons that have been on display for over 80 years. Over the next five years, this historic space will be restored to it’s original neo-classical glory, and eventually remade into a new chronicle of the history of life on Earth suitable for the 21st century.

NMNH was among the last of the classic American natural history museums to commit to a post-dinosaur renaissance overhaul (the American Museum of Natural History started the trend in 1995, followed by the Field Museum and the Carnegie Museum). All eyes are now on the Peabody Museum of Natural History, where the great hall of fossil reptiles still looks much as it did sixty years ago. A plan is in place for a $30 million renovation, and the museum is currently soliciting donations to fund the project. For now, however, New Haven is one of the last places in North America where visitors can still see early-20th century dinosaur mounts.

In With the New

Spinosaurus at the National Geographic Explorer’s Hall. Photo by the author.

Several new temporary and traveling fossil exhibits opened in the United States this year. The biggest splash was made by “Spinosaurus: Lost Giant of the Cretaceous”, which I reviewed in September. Premiering at the National Geographic Explorer’s Hall in Washington DC, this exhibit is science outreach on a grand scale. It debuted alongside a technical paper by Nizar Ibrahim and colleagues that redescribed the well-known Spinosaurus as a short-legged analogue to early whales. While there has been someskepticism about the paper’s conclusions, credit must be given for such an ambitious public display of up-to-the-minute research. The exhibit, which includes a 50-foot reconstruction of a swimming Spinosaurus skeleton, will be on display in Washington through April 12. After that, it begins its world tour in Germany.

Washington, DC got a second new paleontology exhibit this Fall in the form of “The Last American Dinosaurs” at NMNH. Focusing on the North American ecosystem that existed just before the Cretaceous-Paleogene extinction event, this exhibit will serve as an interim dinosaur attraction while the main fossil hall is being renovated. The Last American Dinosaurs is more than a stopgap, however – it’s a remarkably well-crafted look at ecology and the phenomenon of extinction, both in the past and in the present.

Mount of the Year

Sophie the Stegosaurus at the Natural History Museum in London. Source

What was the coolest mounted fossil skeleton created this year? For the runner up, I’d pick the aforementioned Spinosaurus. Created by RCI and Acme Design under the direction of Paul Sereno’s lab at the University of Chicago, this replica skeleton embodies both the possibilities and pitfalls of digital technology. The Spinosaurus mount is based on a digital composite of laser-scanned fossils held in at least three countries, as well as scaled-up bones from related animals like Suchomimus, and a fair amount of sculpted material. On one hand, it’s incredible that a unified vision of this animal can be willed into three-dimensional existence. However, one could reasonably voice concern about presenting a somewhat controversial hypothesis in a format that implies authenticity. Virtually all fossil mounts are composites to some degree, but it seems we’re still working out the limits of how far this concept can be taken.

In contrast, I have no reservations in granting Mount of the Year to Sophie the Stegosaurus. Unveiled on December 4th at London’s Natural History Museum, this is the most complete Stegosaurus specimen known and the first example of this species to be displayed in Europe. It’s also the first new dinosaur skeleton to be added to historic NHM exhibit halls in more than a century. After the museum purchased the skeleton from a private dealer in 2013, Paul Barrett and Charlotte Brassey have been carefully examining (and laser-scanning) every inch of it for the better part of the last year. New data on the biomechanics and behavior of Stegosaurus is due out soon, but for now the public can enjoy the 18-foot skeleton in a dramatic display at the museum. In addition to the impressive work creating a dynamic pose with nearly invisible supports, I’m particularly taken by NHM’s outreach efforts, which explain the importance of this skeleton for a broad range of audiences.

All in all, 2014 was a pretty good year for paleontology on display. While fossil exhibits remained stagnant for much of the 20th century, the last decade plus has seen an explosion of displays to feed the public’s insatiable appetite for dinosaurs. Perhaps in the future we will call this time the second golden age of fossil mounts!

Since the National Museum of Natural History fossil halls closed for renovation this past April, I’ve made a habit of checking the webcam in Hall 2 every couple weeks or so. For a while, it didn’t look like much was happening – the first waves of de-installation occurred out of view, toward the back of the gallery. Eventually, however, the iconic dinosaur mounts started coming down. The Allosaurus vanished in mid-July. The Stegosaurus and Camptosaurus were gone in September. By late October, the exhibit team had started cutting back the elevated platform and surrounding walkway where most of the standing dinosaur mounts had stood. This was when the process got really interesting, because previous renovations to this space over the past century have always been additive. Old exhibit panels were boarded over and forgotten decades ago, and even some elements of the 1911 Hall of Extinct Monsters, such as the John Elliot fresco “Diana of the Tides”, are still buried in these walls. To hear about these time capsules of science history being unsealed over the past few months has been absolutely thrilling.

But when I checked the webcam last Tuesday, I was met with a slight sinking feeling. The Diplodocus, the centerpiece of this hall for the last 83 years, was gone.

After it was excavated from Dinosaur National Monument in 1923, USNM 10865 took Charles Gilmore, Norman Boss, Thomas Horne, and John Barrett nearly a decade to prepare and mount. Aside from an an adjustment to the neck supports in the early 80s (making it hang from the ceiling, rather than being propped up from the floor), the Diplodocus remained in place and unmodified for longer than the average American lifespan. Generations of visitors have gazed up at it, and those lucky enough to view it before 1963 were able to walk under it. This mount has unquestionably taken on a second life: it is an institutional and regional icon as much as it is a dinosaur that once roamed a Jurassic floodplain. And in three days, NMNH collections staff and specialists from Research Casting International cleared every trace of it – well over 200 individual bones – from the hall.

I can’t help but feel a twinge of sadness to see the Diplodocus go. I’ve been visiting the sauropod since before I could talk. I knew it as a toddler, as a high school volunteer, as a fresh-out-of college-intern, and as a museum professional. Even though the fossil halls have been closed for months, I suppose it was comforting to know that the Diplodocus was still standing on the other side of those barriers. But now it’s actually gone, and that makes it really sink in that the NMNH fossil hall that I knew – the one that inspired and nurtured my life-long interest in paleontology, is gone for good.

An early sketch of USNM 10865’s new home – anchoring the Jurassic ecosystem display.

Of course, the now-disarticulated Diplodocus fossils are in the best possible hands. The veteran team at RCI will conserve, restore, and eventually remount them in a stunning, dynamic pose. What’s more, the renovated fossil hall in which it will be reintroduced is going to be awesome – structurally, aesthetically, and pedagogically. It will contextualize classic specimens like the Diplodocus within a modern understanding of how the ancient past is connected to our present and future, while simultaneously honoring this space’s history and heritage. I can’t wait.